Chapter 3 Assignment:
1. If you had a mole of US dollar bills equally distributed to each person in the world, how wealthy
would each person be? Assume a world population of 6 billion.
2. The element rhenium has two naturally occurring isotopes, Re-185 and Re-187 with an average
atomic mass of 186.207amu. Rhenium is 62.60% Re-187 which has a mass of 186.956amu.
Calculate the mass of Re-185.
3. Diamond is a natural form of pure carbon. What number of atoms of carbon are in a 1.00carat
diamond (1.00 carat=0.200g)
4. How many moles of compound are present in1.00g of:
a. NH3
b. N2H4
5. What mass of nitrogen is present in 5.00moles of each compound in question 4?
6. What number of atoms of nitrogen is present in 1.00g of each compound in question 4?
7. What is the molar mass of vitamin C (C6H8O6)? If a typical tablet contains 500.0mg of vitamin C,
what amount, in moles, and what number of molecules of vitamin C does it contain?
8. One anabolic steroid is fluorxymesterone (C20H29FO3). Calculate the percent composition by
mass of each element in the steroid.
9. Place the following in order of increasing mass percent of nitrogen
a. NO
b. NO2
c. N2O4
d. N2O
10. Express the composition of each of the following compounds as the mass percents of its
elements.
a. CH2O
b. C6H12O6
c. HC2H3O2
11. A compound containing only sulfur and nitrogen is 69.9% sulfur by mass; the molar mass is
184g/mol. what are the empirical and molecular formulas?
12. Adipic acid is composed of 49.31%C, 43.79%O, and the rest hydrogen. If the molar mass of
adipic acid is 146.1g/mol, what are the empirical and molecular formulas of the compound?
13. Maleic acid is composed of 41.39%C, 3.47%H and the rest oxygen. If 0.129moles of maleic
acidhas a mass of 15.0g, what are the empirical and molecular formulas?
14. Give the balanced equation for each of the following chemical reactions:
a. Glucose(C6H12O6) reacts with oxygen gas to produce gaseous carbon dioxide and water
vapor
b. Solid Iron(III) sulfide reactis with gaseous hydrogen chloride to form solid iron (III)
chloride and hydrogen sulfide gas
c. Carbon disulfide liquid reacts with ammonia gas to produce hydrogen sulfide gas and
solid ammonium thiocyanate (NH4SCN)
15. Fe2O3 +2Al →2Fe +Al2O3
a. What masses of Iron (III) oxide and aluminum must be used to produce 15.0g of iron?
b. What is the maximum mass of aluminum oxide that could be produced?
16. KClO3 + P4 →P4O10 + KCl (unbalanced)
a. If you were to react 52.9g of potassium chlorate with excess red phosphorus, what mass
of tetraphosphorus decaoxide would be produced?
17. 3Al + 3NH4ClO4→Al2O3 + AlCl3 +3NO + 6H2O
a. What mass of ammonium perchlorate should be used in the fuel mixture for every
kilogram of aluminum?
18. Bacterial digestion is an economical method of sewage treatment. The reaction
5CO2 + 55NH4+ + 76O2→C5H7O2N (bacterial tissue) + 54NO2- + 52H2O + 109H+
a. What mass of bacterial tissue is produced in a treatment plant for every 1.0x104 kg of
wastewater containing 3.0% NH4+ ions by mass? Assume that 95% of the ammonium
ions are consumed by the bacteria.
19. Phosphorus can be prepared from calcium phosphate by the following reaction:
2Ca3(PO4)2 + 6SiO2 + 10C→6CaSiO3 + P4 + 10CO
a. Phosphorite is a mineral that contains about 75% calcium phosphate by mass. What is
the maximum amount of phosphorus that can be produced from 1.0kg of phosphorite?
Pg 121 (97, 101-105)
20. Hydrogen cyanide is produced industrially from the reaction of gaseous ammonia, oxygen and
methane: 2NH3 + 3O2 +2CH4→2HCN +6H2O
a. If 5.00x103kg of each reactant react, what mass of HCN and of H2O will be produced,
assuming 100% yield?
21. 2C3H6 +2NH3 + 3O2 →2C3H3N + 6H2O.
a. If 15.0g of C3H6, 10.0g oxygen, and 5.00g of ammonia are reacted what mass of C3H3N
can be produced, assuming 100% yield?
22. 2C6H5Cl + C2HOCl3 →C14H9Cl5 + H2O
a. 1142g of C6H5Cl is reacted with 485g of C2HOCl3.
i. What mass of C14H9Cl5 is formed?
ii. Which reactant is limiting? Which is excess?
iii. What mass of the excess reactant is left over?
iv. If the actual yield is 200.0g, what is the percent yield?
23. 2Cu3FeS3 + 7O2 →6Cu + 2FeO + 6SO2.
a. If 2.50metric tons (1000kg) of Cu3FeS3 is reacted with excess O2 and the process has an
86.3% yield of copper, what mass of copper is produced?